In the process of manufacturing semiconductor devices or flat panel display devices (FPD), liquid processes are frequently used, in which a process liquid is supplied onto a target substrate, such as a semiconductor wafer or glass substrate. For example, processes of this kind encompass a cleaning process for removing particles and/or contaminants deposited on a substrate, and a coating process for applying a photo-resist liquid or development liquid in a photolithography sequence.
As a liquid processing apparatus used for this purpose, the following apparatus of the single-substrate processing type is known. Specifically, a substrate, such as a semiconductor wafer, is held on a spin chuck, and a process liquid is supplied onto the front surface or front and back surfaces of the wafer, while the wafer is rotated. Consequently, a liquid film is formed on the front surface or front and back surfaces of the wafer, thereby performing a process.
In general, an apparatus of this kind is arranged to supply a process liquid onto the center of a wafer, and rotate the wafer to spread the process liquid outward, thereby forming a liquid film and throwing off the process liquid. A surrounding member, such as a cup, is disposed around the wafer to guide downward the process liquid thrown off from the wafer, so that the process liquid is swiftly drained. However, where such a cup or the like is used, part of the process liquid may bounce back to the wafer as mist, and generate defects thereon, such as water marks and/or particles.
As a technique for preventing this problem, Jpn. Pat. Appln. KOKAI Publication No. 8-1064 discloses a technique which utilizes a process liquid receiving member to be rotated integrally with rotary support means that rotates along with a substrate held thereon in a horizontal state. The process liquid receiving member receives a process liquid scattered around the substrate, and guides the process liquid outward to collect it. According to this Jpn. Pat. Appln. KOKAI Publication No. 8-1064, the process liquid receiving member includes a horizontal eaves portion, an inclined guide portion for guiding the process liquid outward and downward, a horizontal guide portion for guiding the process liquid outward in the horizontal direction, and a wall portion extending upward in the vertical direction, in this order from the substrate side. With this arrangement, the process liquid is guided into a narrow space to prevent mist from bouncing back onto the substrate, while the process liquid is drained from a drain port formed at a corner of the process receiving member. The process liquid is then discharged through grooves extending outward within a spacer disposed around the process liquid receiving member.
Where a liquid process of this kind is performed, a process liquid is deposited on the process liquid receiving member. In this sate, if the liquid process is performed on a substrate, the deposited process liquid may generate particles, which are then transferred onto the substrate. In order to solve this problem by a simple mechanism, a technique of supplying a cleaning liquid from a nozzle disposed inside a cup for receiving a process liquid (for example, Jpn. Pat. Appln. KOKAI Publication No. 9-232276) may be usable.
However, the process liquid receiving member disclosed in Jpn. Pat. Appln. KOKAI Publication No. 8-1064 is arranged to rotate along with a substrate at a high speed, so the process liquid reaches portions not only inside but also outside the process liquid receiving member. Accordingly, the technique disclosed in Jpn. Pat. Appln. KOKAI Publication No. 9-232276 is unsuitable for the structure disclosed in Jpn. Pat. Appln. KOKAI Publication No. 8-1064.